MXPA05006180A

MXPA05006180A - Process for applying a polyurethane dispersion based foam to an article.

Info

Publication number: MXPA05006180A
Application number: MXPA05006180A
Authority: MX
Inventors: Randal E Autenrieth
Original assignee: Dow Global Technologies Inc
Priority date: 2002-12-09
Filing date: 2003-11-20
Publication date: 2006-05-25
Also published as: US20040109992A1; ZA200504269B; JP2006508836A; WO2004053223A3; BR0316329A; CN1723312A; KR20050085483A; EP1573119A2; WO2004053223A2; CA2506542A1; AU2003295757A1

Abstract

Disclosed is a process for making a two or more component foam composite obtained by adhesion of a polyurethane foam onto a substrate comprising the steps of frothing an aqueous polyurethane formulation; applying the froth to a substrate and drying the froth into a foam wherein the foam has a dry density of 35 kg/m3 to 160 kg/m3 (2.2-10 Ibs/cft). The process allows the production of foam backed textiles without the need for a flame lamination step or the need for an adhesive layer between the textile and the foam layer and is optionally optimized for superior handling properties for covering polyurethane molded foam cushions.

Description

PROCESS TO APPLY TO AN ARTICLE A FOAM BASED ON A DISPERSION OF POLLURETHANE This invention relates to a thin-film substrate of pre-coated polyurethane foam, and to articles containing said substrate. More particularly, the invention relates to a mixed cover material comprising articles on a roll consisting of a fabric, a textile or a plastic, having a thin layer of foamed polyurethane, adhered to its back or internal surface, and a process to prepare them. Foam backed materials, particularly fabrics, are used in a variety of applications, such as automotive applications, for example, in vehicle seats, seat cushions, headrests, automotive interior linings, armrests, sun visors, door panels, shelves for parcels and for use in furniture upholstery, and bedding. Foam-backed fabrics such as absorbers or absorbent layers for various textiles and disposable articles may also be useful. Such fabrics with foam backing are generally prepared in several steps. Initially a foam is prepared by reacting a polyisocyanate and a polyol and other auxiliary components, under conditions known to those skilled in the art, and then slicing or peeling the foam to a desired thickness. In order to adhere the foam to a fabric, the fabric may optionally be impregnated with a water-based polymer binder, typically an acrylic-based polymer, to provide adequate dimensional stability and hardness and, subsequently, in a separate process, it is attached the treated fabric to the foam scraped by flame lamination or by adhesive bonding. The flame lamination process and the adhesive bonding process imply that various manufacturing operations must be carried out in different locations, for example, the manufacturer ships the flame retardant fabric or the adhesive bonding machine, which may or may not also be the foamer; then mixed fabric is shipped back to be cut and sewn as a seat cover and / or assembled as a seat before being shipped to the automotive OEM. In addition to logistics, the processes of flame lamination and bonding with adhesive have disadvantages related to the emissions of volatile organic compounds, either from the decomposition of the molten polyurethane polymer, in the case of the flame rolling process, or the elimination of the organic solvent from the bonding process with adhesive. Alternatively, a soft foam article having an integrally bonded cover can be produced by providing a permeable cover fabric in the form of a desired final article and pouring a formulation of the same onto the formed cover fabric placed in the mold. polyurethane foaming with reagent, to form a molded foam, which adheres integrally with the cover fabric. The undesirable foam properties may be the result of the poured material permeating into or through the cover fabric. When liquid material is applied directly to the inner surface of the permeable fabric, soaking may occur through it before and during chemical and thermal foaming, which would result in the formation of partially rigid areas or hard spots in the fabric, which are unpleasant to the touch and that do not meet the quality specifications of the automotive industry. Alternatively, for the purposes of preventing the penetration or impregnation of the body foam into the cover fabric, techniques are proposed in several US patents to apply an air tight film to the interior surface of the cover fabric. For example, US patents 4,247,347, 4,247,348, 4,264,386 and 4,287,143 describe the application of air-tight films, preferably polyvinyl chloride film., to the rear surface of the cover fabric. Said air tight or waterproof films, however, deprive the final foamed article of the permeability and breathing capacity that leads to an uncomfortable feeling, such as a touch of moisture or stickiness on the surface of the article. To avoid some of these disadvantages, it is proposed in US Pat. No. 5,460,873 to prepare a mixed cover material using a thin layer of latex foam bonded to the fabric. The lack of significant commercialization of this latter invention can be explained by the inadequate property performance profiles of previously available foam systems, such as styrene-butadiene polymers, at competitive cost densities, while the use of Higher densities contribute to prohibitively increase the weight. Therefore, it would be advantageous to have a simplified process for producing a mixed material having a foamed backing or support with higher operating efficiency and reduced emission of volatiles generated during production. In particular, a process that creates a suitable product and avoids the need for multi-step processes, including a flame lamination process, bonding with adhesive, or the need to have a non-permeable layer with the substrate. It would also be advantageous if said articles produced had modified combustion properties, which would allow greater freedom of selection of the fabric used for covers, at the same time as the requirements of the OEM are satisfied. In one aspect, the invention is a process for forming a mixed structure of foam of two or more components, obtained by adhesion of a polyurethane foam on a substrate, comprising the steps of: foaming an aqueous dispersion formulated from polyurethane; Apply the foam to a substrate, and dry the foam to a dry foam, where the foam has a dry density of 35 kg / m3 to 160 kg / m3 (2.2-10 Ibs / cft).

In another aspect, the invention is a process for forming a mixed structure of two or more components, without the use of a flame lamination process or the use of adhesive binder layers, comprising the steps of foaming an aqueous dispersion formulated from polyurethane; Apply the foam to a textile, and dry the foam to a dry foam, where the dry foam has a dry density of 35 kg / m3 to 160 kg / m3 (2.2-10 Ibs / cft), and the mixed structure of foam passes the combustion modification test FMVSS 302. In another aspect, the invention is the production of a mixed foam structure, where a flame retardant is added to a polyurethane dispersion, in an amount sufficient that, when preparing a foam from the dispersion, the foam passes the FMVSS 302 combustion modification test. Other components can be added to the polyurethane dispersion, so that the final dispersion contains from 50 to 95 parts by weight of dry solids. In a further aspect, the invention is the production of a mixed foam structure, where the surface properties of the foam are suitably modified to increase the coefficient of friction on the surface, for improved ease of handling when handling the fabric in applications of end use, such as in car seats. Said modification of the surface properties of the foam can be achieved in several different ways. First, the addition of suitable additives, such as waxes, to the formulated polyurethane dispersion or to the polyurethane compound, prior to foaming, leads to outcrop of the wax to the foam surface during the drying step, which increases the slipperiness of the surface. Secondly, the application of a water-based spray coating, such as a silicone, to the surface of the dry foam, coming out of the oven, which dries to a slippery film on the foam surface of the mixed structure Hot or warm, to roll the items in roll, to storage rolls. Third, a hot lamination of a thin film, such as a lightweight, non-woven polyethylene, such as "pink poly" (INTEGRAL ™ 899 and DAF ™ 780, obtainable from The Dow Chemical Company), directly to the surface of the dry foam film, through a pressure roller, after leaving the drying oven and before winding the articles to storage rolls. Fourth, a cloth can be laid on the wet foam after drying the wet foam and the entire mixed structure is dried by a single drying step. In one embodiment, the present invention is a process for producing a mixed foam structure by adhering a polyurethane foam to a substrate, applying a polyurethane foam to the substrate. When the substrate is a textile, the process eliminates the need for a flame lamination process, or the need for a binder or adhesion layer between the textile and the scraped foam produced separately. The present process also eliminates the need to have a non-permeable layer between a permeable textile and the applied formulation of a foam, in order to avoid or reduce the scratchy fabric due to the soaking of the formulation within the fabric. The elimination of the flame lamination process reduces the number of steps necessary to produce the mixed foam structure and avoids the emissions associated with the flame lamination process. With the addition of certain selected flame retardants it was unexpectedly found that the mixed materials satisfy certain mandatory flame retardant properties, without the need for the presence of a halogenated flame retardant. It was surprisingly found that a water-based polyurethane dispersion, formulated with 35 to 80 parts by weight solids, can be formulated while obtaining a final foam density of only 35 to 40 kg / m 3., and an elasticity of 10 to 50 percent. It was further discovered that the mixed structures produced from that dispersion, combined with a combustion modifying agent, can pass the FMVSS 302 combustion modification test. The use of said polyurethane dispersions is advantageous over other aqueous polymer systems, such like styrene-butadiene latexes. These latexes are well known for being able to provide mechanically foamed foams. However, the physical properties of the low density materials obtained from these dispersions do not meet the functional requirements of the products laminated or bonded with adhesive, which refer to flames. A polyurethane dispersion, useful in the practice of the present invention, includes water and one of the following: a polyurethane, a mixture capable of forming a polyurethane, and / or surfactants. The polyurethane-forming materials that are used in the present invention are materials that can be used to prepare polyurethane polymers. Polyurethane-forming materials include, for example, polyurethane prepolymers. While the polyurethane prepolymers retain some of the isocyanate reactivity for a certain time after dispersion, for the purposes of the present invention a polyurethane prepoiimer dispersion will be considered to be a fully reacted polyurethane polymer dispersion. Further, for the purposes of the present invention a polyurethane prepolymer or a polyurethane polymer may include other types of structures, such as, for example, urea groups. The polyurethane prepolymers useful in the practice of the present invention are prepared by reacting active hydrogen compounds with any amount of isocyanate in a stoichiometric excess relative to the active hydrogen material. The isocyanate functionality in the prepolymers useful with the present invention may be present in an amount of 0.2 weight percent to 20 weight percent. A suitable prepoiimer may have a molecular weight within the range of 100 to 10,000.

The prepoiomers useful in the practice of the present invention should be substantially liquid under the conditions of dispersion. The prepolymer formulations of the present invention include a polyol component. The active hydrogen-containing compounds most commonly used in the production of polyurethane are those compounds having at least two hydroxyl groups or amine groups. These compounds are referred to herein as polyols. Representatives of suitable polyols are generally known and described in publications such as High Polymers, Volume XVI Polyurethanes, Chemlstry and Technology, by Saunders and Frisch, Interscience Publishers, New York, Volume I, pages 32-42, 44-54 ( 1962) and volume II, pages 5-6, 198-199 (1964); Organic Polymer Chemistry by K. J. Saunders, Chapman and Hall, London, pages 323-325 (1973); and Developments in Polyurethanes, volume I, J.. Burst, ed., Applied Science Publishers, pages 1.76 (1978). However, any compound containing active hydrogen can be used with the present invention. Examples of those materials include those selected from the following classes of compositions, alone or in admixture: (a) polyhydroxyalkane adducts with alkylene oxide; (b) adducts of non-reducing sugars and sugar derivatives, with alkylene oxide; (c) adducts of phosphorus and polyphosphorus acids with alkylene oxide; and (d) polyphenol adducts with alkylene oxide. Polyols of these types are referred to herein as "base polyols". Examples of polyhydroxyalkane adducts with alkylene oxide, useful herein, are the adducts of ethylene glycol, propylene glycol, 1,3-dihydroxypropane, 1,4-dihydroxybutane and 1,6-dihydroxyhexane, glycerol, 1, 2,4- trihydroxybutane, 1,2,6-dihydroxyhexane, 1,1-trimethylolethane, 1,1-trimethylolpropane, pentaerythritol, polycaprolactone, xylitol, arabitol, sorbitol, mannitol. Preferred herein are as adducts of polyhydroxyalkanes with alkylene oxide the adducts of dihydroxyalkanes and trihydroxyalkanes with propylene oxide and the adducts of dihydroxyalkanes and trihydroxyalkanes with propylene oxide capped with ethylene oxide. Other useful alkylene oxide adducts include the adducts of ethylene diamine, glycerin, piperazine, water, ammonia, 1,2,3,4-tetrahydroxybutane, fructose, sucrose. Also useful in the present invention are poly (oxypropylene) glycols, triols, tetroles and hexols, and any of these which is capped with ethylene oxide. These polyols also include the poly (oxypropyleneoxyethylene) polyols. The oxyethylene content should preferably comprise less than about 80 weight percent of the total weight of polyol and, more preferably, less than about 40 weight percent. When used, the ethylene oxide can be incorporated in any way along the polymer chain, for example, as internal blocks, as terminal blocks or as randomly distributed blocks, or any combination thereof. Polyester polyols can be used to prepare the polyurethane dispersions of the present invention. Polyester polyols are generally characterized by repeating ester units which may be aromatic or aromatic, and by the presence of terminal primary or secondary hydroxyl groups; but any polyester that ends in at least two active hydrogen groups can be used in the present invention. For example, the reaction product of the transesterification of glycols with polyethylene terephthalate can be prepared to prepare the dispersions of the present invention. For polyurethane dispersions, preferably at least 50 weight percent of the active hydrogen compounds, used to prepare the polyurethane or the polyurethane prepolymer, is a polyether polyol having a molecular weight of 600 to 20,000, preferably from 1,000 to 10,000, very preferable, from 3,000 to 8,000. It is preferred that the polyol has a hydroxyl functionality of at least 2.2. It is preferable that this polyol has a hydroxyl functionality of 2.2 to 5.0, more preferably, of 2.3 to 4.0, and still more preferable, of 2.5 to 3.8. Most preferred is that the active hydrogen compounds used to prepare the polyurethane or the polyurethane prepolymer is a polyether polyol having a hydroxyl functionality of 2.6 to 3.5 and a molecular weight of 3,000 to 8,000. For the purposes of the present invention, functionality is defined as meaning the average of the calculated average functionality of all polyol initiators, further adjusted for any known side reactions that affect functionality during the production of the polyol. The polyisocyanate component of the formulations of the present invention can be prepared using any organic polyisocyanates, modified polyisocyanates, isocyanate-based prepolymers and mixtures thereof. They may include aliphatic and cycloaliphatic isocyanates, but aromatic isocyanates and, especially, multifunctional aromatic isocyanates, such as 2,4- and 2,6-toluene diisocyanate, and the corresponding isomer mixtures are preferred.; 4,4 ', 2,4', and 2,2'-diphenylmethane diisocyanate (MDI) and the corresponding isomeric mixtures; mixtures of 4,4'-, 2,4'- and 2,2'-dienylmethane diisocyanates and polyphenylenepolymethylene polyisocyanates (PMDI), and mixtures of PMDI and toluene diisocyanates. Most preferred is that the polyisocyanate used to prepare the prepoxymer formulation of the present invention is MDI or PMDI or crude mixtures of any of these. The prepolymers for use in the present invention include a chain extender or interleaver. A chain extender is used to construct the molecular weight of the polyurethane prepolymer by reaction of the chain extender with the isocyanate functionality in the polyurethane prepolymer; that is, extending the chain of the polyurethane prepoxymer. The chain extenders typically have two or more active hydrogen groups, while the crosslinkers have three or more active hydrogen groups. The active hydrogen groups can be hydroxyl, mercaptyl or amino groups. An amine chain extender can be blocked, encapsulated or otherwise reactive less reactive. Other materials, in particular water, can function to extend the chain length and, therefore, can be chain extenders for the purposes of the present invention. Polyamines are preferred as chain extenders and / or as interleavers. It is particularly preferred that the chain extender be selected from the group consisting of amine terminated polyethers, such as, for example, JEFFAMINE D-400, from Hutsman Chemical Company, aminoethylpiperazine, 2-methylpiperazine, 1,5-diamino-3. -methylpentane, isophorone diamine, ethylenediamine, diethylenetriamine, aminoethylethanolamine, triethylenetetraamine, triethylene-pentaamine, ethanolamine, lysine in any of its stereoisomeric forms, and its salts; Hexanediamine, hydrazine and piperazine. In the practice of the present invention, the chain extender can be used as an aqueous solution. In the formation of the dispersion, a chain extender is used in an amount sufficient to react from zero (0) to 100 percent of the isocyanate functionality present in the prepolymer, based on an isocyanate equivalent that reacts with an equivalent of chain extender It may be convenient to let the water act as a chain extender and to react some or all of the isocyanate functionality present. A catalyst can optionally be used to promote the reaction between a chain extender and an isocyanate. When the chain extenders of the present invention have more than two active hydrogen groups, they can also function concurrently as interleavers. The surfactants useful for preparing a stable dispersion can be cationic surfactants, ammonium surfactants or nonionic surfactants. Examples of anionic surfactants include: sulfonates, carboxylates and phosphates. Examples of cationic surfactants include quaternary amines. Examples of nonionic surfactants include block copolymers containing ethylene oxide, propylene oxide, butylene oxide, or a combination thereof and silicone surfactants. The surfactants useful in a polyurethane dispersion may be external surfactants or internal surfactants. The external surfactants are surfactants that are not chemically reacted in the polymer during the preparation of the dispersion. Examples of external surfactants, useful herein, include the salts of dodecylbenzenesulfonic acid and the salt of lauryl sulphonic acid. The internal surfactants are surfactants which are not chemically reacted in the polymer during the preparation of the dispersion. An example of an internal surfactant useful herein includes the acid 2, 2- dimethylolpropionic acid (DMPA) and its salts, or sulfonated polyols neutralized with ammonium chloride. A surfactant may be included in a formulation of the present invention, in an amount ranging from 0.01 to 8 parts per 100 parts by weight of polyurethane component. Currently, most commercially available polyurethane dispersions contain DMPA as an internal surfactant, and can be used in the present invention. In contrast, a polyurethane dispersion family that does not contain DMPA, which incorporates non-ionic modifiers based on ethylene oxide, as internal surfactants, are equally suitable for practicing the present invention, providing other technical and commercial advantages to the process . See, for example, U.S. Patent 6,271,276. In general, any method known to those skilled in the art can be used to prepare polyurethane dispersions. Here a suitable polyurethane dispersion during storage is defined, suitable, as any polyurethane dispersion having an average particle size of less than about 5 microns. A polyurethane dispersion that is not stable during storage can have an average particle size of more than 5 microns. For example, a suitable dispersion can be prepared by mixing a polyurethane prepolymer with water and dispersing the prepolymer in the water, using a mixer. Alternatively a suitable dispersion can be prepared by feeding a prepolymer in a static mixing device together with water, and dispersing the prepolymer in the water using a mixer. Alternatively a suitable dispersion can be prepared by feeding a prepolymer in a static mixing device together with the water, and dispersing the water and the prepolymer in the static mixer. Continuous methods for preparing aqueous polyurethane dispersions are known and can be used in the present invention. For example, U.S. Patent Nos. 4,857,565, 4,742,095, 4,879,322, 3,437,624, 5,037,864, 5,221,710, 4,237,264 and 4,092,286 describe all continuous processes useful for preparing polyurethane dispersions. In addition, a polyurethane dispersion having a high proportion of internal phase can be prepared by a continuous process, such as that described in U.S. Patent No. 5,539,021. A suitable polyurethane formulation can be prepared to prepare a foam for use in the present invention (hereinafter referred to as the compound), from a polyurethane dispersion and foaming surfactants and foam stabilizers. It has been surprisingly discovered that by using a selection of surfactant foaming agents and stabilizers, or combinations thereof, a lower density foam can be obtained, while maintaining the desired foam properties, such as abrasion resistance, traction , tearing and lengthening (TTE); permanent compression deformation, foam recovery, wet strength, tenacity and adhesion to the substrate. Since optimizing a property will affect the values of the other properties, a person skilled in the art can vary the scales of those properties to maintain a combination of acceptable values. For example, for a foam having an approximate density of 35 kg / m 3, the foam properties generally acceptable in the industry include an elasticity of more than 30 percent, when measured by ASTM D-3574; a minimum tensile strength (MPa) of 78, when measured by ASTM D-3574; and an elongation of more than 120 percent, when measured by ASTM D-3574. For a foam having an approximate density of 40 kg / m3, the foam properties generally acceptable by the industry include an elasticity of more than 28 percent; a minimum tensile strength (MPa) of 196; and an elongation of more than 140 percent. In general, the foam prepared from the foamed dispersions will have a density of 35 kg / m 3 to 160 kg / m 3. Preferably the foam will have a density of 40 to 150 kg / m3. It is more preferred that the foam has a density of 50 to 120 kg / m3. What is most preferred is a foam with a density of 60 to 80 kg / m3. The surfactants useful for preparing a foam are called foaming surfactants herein. A surfactant foaming agent allows the gas, commonly air, used for foaming, to be dispersed homogeneously and efficiently within the foamed formulated dispersion. Preferably the foaming surfactant produces a non-foaming mixed composition product after drying. The foaming surfactants for preparing the low density foams of the present invention can be selected from anionic, cationic or hybrid surfactants. An example of an anionic surfactant used generally is sodium lauryl sulfate; however, this surfactant has the disadvantage of foaming subsequently in the final foam product. Preferably, the foaming surfactant is a carboxylic acid salt. Said surfactants can be represented by the general formula: RCO "X + (Formula I) wherein R represents a linear or branched alkyl of 8 to 20 carbon atoms, which may contain an aromatic, a cycloaliphatic or a heterocycle, and X is a In general, X is Na, K or an amine, such as NH +, morpholine, ethanolamine, triethanolamine, and others, preferably R has from 10 to 18 carbon atoms, it is more preferable that R contains 12. The surfactant may contain a plurality of different R species, such as a mixture of alkyl salts of 8 to 20 carbon atoms, of fatty acids, preferably X is an amine. The surfactant is an ammonium salt, such as ammonium stearate The amount of foaming agent (s) used is based on the content of dry solids present in the surfactant with respect to the solids of the dispersion. polyurethane, in parts po r hundred parts. Generally, from 1 to 15 parts of dry surfactant is used per one hundred parts of polyurethane dispersion. It is preferable that from 1 to 10 parts of dry surfactant is used per one hundred parts of polyurethane dispersion. It is more preferred that 1 to 5 parts of dry surfactant is used per one hundred parts of polyurethane dispersion. The use of higher levels of foaming surfactants is possible, at the same time as the levels of the stabilizing surfactants are reduced, but it is not convenient, due to the increased addition of water at the same time. The high levels of surfactant further have other detrimental effects on the mixed foam compositions, such as increased haze and increased fouling. The surfactants useful for preparing a stable foam are referred to herein as stabilizing agents. The stabilizing surfactant used to produce the low density foam of the present invention is based on sulfonic acid salts, such as sulfates, such as alkylbenzenesulfonates, succinamates and sulfosuccinamates. The preferred sulfates are the class of sulfosuccinate esters that can be represented by the general formula: R2OOCCH2CH (S03"M +) COOR2 (Formula 2) wherein R2, in each occurrence, is independently a linear or branched alkyl of 6 to 20 carbon atoms, which may contain an aromatic, a cycloaliphatic, and M is an ion In general, M is ammonia or a member of group 1A of the Periodic Table, such as lithium, potassium or sodium, It is preferred that R2 has from 8 to 20 carbon atoms, it is preferred that R2 contains from 10 to 18. carbon atoms The surfactant may contain, in each occurrence, a different species R 2, preferably R is an amine It is more preferred that the surfactant be an ammonia salt It is preferable that the stabilizing surfactant is a salt of an octadecyl sulfosuccinate Generally 0.01 to 20 parts of dry surfactant is used per one hundred parts of polyurethane dispersion, preferably from 0.05 to 10 parts of dry surfactant per one hundred parts of polyurethane dispersion. , plus preferably, from 0.1 to 6 parts of dry surfactant per one hundred parts of polyurethane dispersion. In addition to the combination of anionic surfactants given above, preferably the composite will also contain a hybrid surfactant to increase foaming and / or foam stability. The preferred hybrid surfactants are the N-alkylbetaines, preferably they are the beta-alkyl propionic acid derivatives. The N-alkylbetaines may be represented by the general formula.

Said surfactants may be represented by the general formulas: R3N + (CH3) 2CH2COCriVI + (formula 3) R3N + C | -M + or (formula 4) R3N + Br "M + (formula 5) wherein R3 is a linear or branched alkyl, 6 to 20 carbon atoms, which may contain an aromatic, a cycloaliphatic, and R and are as described above.When used generally 0.01 to 5 parts of dry hybrid surfactant per hundred parts of dispersion are used. It is preferred to use 0.05 to 4 parts of dry surfactant per one hundred parts of polyurethane dispersion.The anionic and hybrid surfactants given above can be obtained commercially.In addition to the surfactants listed above, they can be using other surfactants which do not detrimentally affect the foaming or the stability of the foam In particular, other anionic, hybrid or non-ionic surfactants may be used in combination with the surfactants from the previous list. In addition to a dispersion of polyurethane and surfactants foamers and stabilizers, it is preferred that the compound contains a flame retardant. It has been found, surprisingly, that the level of inorganic filler and desired physical properties of a final foam can be obtained by the combination of the anionic and hybrid agents, which were given above. The combination of surfactants aids in the dispersion stability of the filler in the composite, and does not adversely affect foaming or foam stability. Flame retardants that can be added to the compound include those typically used to give increased flame retardancy properties to a typical latex foam. Such flame retardants include phosphonate esters, phosphate esters, halogenated phosphate esters, or a combination thereof. Representative examples of phosphonate esters include: dimethyl phosphonate (DMMP) and diethyl ethylphosphonate (DEEP). Representative examples of phosphate esters include triethyl phosphate and tricresyl phosphate. When used, flame retardants of phosphonate or phosphate ester are present in the final foam at a level of 0.5 to 10 weight percent of the final foam. Representative examples of halogenated phosphate esters include: 2-chloroethanol phosphate (C6H12Cl204P); 1-chloro-2-propanol phosphate [tris (1-chloro-2-propyl)] (C8H18CI304P) phosphate (TCPP); 1, 3-dichloro-2-propanol phosphate (C9H15CI60 P), also called tris (1,3-dichloro-2-propyl) phosphate; tri (2-chloroethyl) phosphate; tri (2,2-dichloroisopropyl) phosphate; tri (2,3-dibromopropyl) phosphate; tri (1,3-dichloropropyl) phosphate, tetracis (2-chloroethyl) ethylene diphosphate, bis (2-chloroethyl) 2-chloroethylphosphonate, diphosphates [2-chloroethyl diphosphate], tetracis (2-chloroethyl) ethylenediphosphate, phosphate of tris (2-chloroethyl), tris- (2-chloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate; tris (1,3-dichloropropyl) phosphate; tetracis (2-chloroethyl-ethylene) phosphate ) and tetracis (2-chloroethyl) ethyleneoxyethylene diphosphate When used as a flame retardant, the halogenated phosphate ester will constitute 0.5 to 10 weight percent of the final foam Flame retardants for use in the present invention They are retarders of dehydratable flames, some of which have been used as fillers for certain products.These flame retardants include alkali silicates, zeolites or other hydrous phosphates, borosilicates or borates, alumina hydroxides, cyanuric acid derivatives, melamine powder, graffiti and mica, that are ca swells; vermiculites and pearls, and minerals containing water of crystallization, such as aluminohydrocalcite, hydromagnesite, taumasite and vermlandite. ??? 203 · 3? 20, alumina trihydrate, also known as hydrated aluminum or hydrated alumina oxides, is preferred. The dehydratable flame retardant is generally added to the polyurethane dispersion in an amount of 5 to 120 parts per 100 parts of dispersion solids to the final compound. Preferably, the flame retardant is added in an amount of 20 to 100 parts per 100 parts of dispersion solids in the final compound. It is more preferred that the flame retardant be added in an amount of 50 to 80 parts per 100 parts of dispersion solids of the final compound. The use of said flame retardants of the dehydrating flames allows the production of mixed materials containing a polyurethane which passes certain flammability tests, such as F VSS 302, without the need to use a halogenated flame retardant. The compounds can be applied to textiles, when the textiles themselves satisfy the required combustion modification test. In this case, there is no detrimental effect on the operation of the combustion modification and, in general, combustion modification properties are improved. When the foamed compound is added to a textile which by itself does not approve a specific flammability test, the use of foamed compound with a dehydratable flame retardant will generally increase the combustion modification properties of the final mixed compound. Examples of conventional fillers include: ground glass, calcium carbonate, aluminum trihydrate, talc, bentonite, antimony trioxide, kaolin, ash powder or other known fillers. In the practice of the present invention a suitable filler loaded in a polyurethane dispersion can be from 0 to 200 parts of filler per 100 parts of dispersion solids (pphds) of the final compound. Preferably the charge can be charged in an amount of less than about 100 pphd, most preferably less than about 80 pphd. The addition of inorganic fillers increases the production of the mixed foam composition by faster drying rates in the production line, since the percentage of water in the compound that has to be removed by drying is lower. Optionally, a charge wetting agent may be present. A charge wetting agent generally improves the compatibility of the charge and dispersion of the polyurethane. Useful wetting agents include phosphate salts, such as sodium hexametaphosphate. A charge wetting agent may be included in a compound of the present invention, at a concentration of at least about 0.5 pphds. In addition to a polyurethane dispersion, a combustion modifier and a foam stabilizer, a compound of the present invention may optionally include: crosslinkers, which are different chemical entities from those generally used in the preparation of the polyurethane dispersion (epoxy resins as reactive agents or as dispersion in water, water-dispersible isocyanate, low-reactivity aliphatic isocyanate), fillers, dispersants, thickeners, absorbers, fragrances and / or other materials known in the art as useful in the preparation of polymer foam products. The term "composite" means particularly the material placed in a mechanical foaming unit, to produce a foam that can be dried to form a stable foam.

The present invention optionally includes thickeners. Thickeners may be useful in the present invention to increase the viscosity of low viscosity polyurethane dispersions. Thickeners suitable for use in the practice of the present invention can be any that is well known in the art. For example, suitable thickeners include ALCOGU ™ VEP-II (trademark designation of Aleo Chemical Corporation) and PARAGUM ™ 241 (trademark designation of Para-Chem Southern, Inc.). Other suitable thickeners include cellulose derivatives, such as ethocel ™ products (trademark designation of The Dow Chemical Company). The thickeners can be used in any amount necessary to prepare a compound with the desired viscosity. While optional for the purposes of the present invention, some components may be highly advantageous for the stability and durability of the product during and after the manufacturing process. For example, the inclusion of antioxidants, biocides and preservatives in the compound can be extremely advantageous in the practice of the present invention. To prepare a foam from the compound, a gaseous frothing agent is generally used. Examples of suitable foaming agents include: gases and / or gas mixtures, such as, for example: air, carbon dioxide, nitrogen, argon, helium. Foaming agents are typically introduced by introducing a gas above atmospheric pressure into a liquid compound, to form a homogeneous foam by mechanical shear forces, during a predetermined residence time; that is, mechanical foaming. When preparing a foamed polyurethane backing it is preferred to mix all the components of the compound and then combine the gas into the mixture, using equipment such as a skimmer OAKES, COWIE & RIDING or FIRESTONE. Other types of aqueous polymer dispersions can be used in combination with the polyurethane dispersions of the present invention. Suitable dispersions, useful for mixing with polyurethane dispersions of the present invention, include: styrene-butadiene dispersions, styrene-butadiene-vinylidene chloride dispersions; alkyl styrene-acrylate dispersions; ethylene-vinyl acetate dispersions; polychloropropylene latex, polyethylene copolymer latex, ethylene-styrene copolymer latex; polyvinyl chloride latex, or acrylic dispersions, as compounds and mixtures thereof. The polyurethane foams of the present invention are elastic. For the purposes of the present invention, an elastic foam is one that has a minimum elasticity of 5 percent when tested by the falling ball method. This method, ASTM D3574, generally consists of dropping a ball or sphere of known weight, from a standard height, onto a specimen of the foam of specified height, and then measuring the rebound of the ball as a percentage of the height from the that was dropped Preferably, the foams of the present invention have an elasticity of 5 to 80 percent, more preferably, of 10 to 60 percent and, most preferably, of 15 to 50 percent. A polyurethane dispersion of the present invention can be stored for subsequent application to the back of a substrate such as a textile, including leather, plastic films, synthetic sheets, such as PVC, paper, wood laminate floors, building panels, as rock board and metal spirals for profiled panels. Typically, the polyurethane dispersion, usually in the form of a foamed compound, is applied as a stable foam to a substrate surface using equipment such as a spatula or a roller, a pneumatic applicator or a spatula blade to apply and measure the layer. See, for example, U.S. Patents 5,460,873 and 5,948,500. When applying the foam to a textile, the textile is usually heated before adding the foam; see, for example, U.S. Patent No. 5,460,873. Preferably, the textile is heated to 25-50 ° C before the application of the foam. It is believed that heating the textile decreases the viscosity of the liquid foam, which increases the penetration of the textile at the interface. Additionally, it is believed that heating the textile also impacts the surface tension, which improves the compatibility between the foam and the textile. After the foam is applied to a substrate, the material is treated in such a manner that substantially all of the water present in the foam is removed, resulting in a material that is a mixed composition containing an elastic polyurethane foam cell. The elimination of water is usually effected by the use of a power source, such as an infrared oven, a conventional oven, microwaves or heating plates. Preferably drying is carried out by addition of heat. Drying can be carried out at room temperature, but preferably in an oven at temperatures of 50 to 200 ° C. The amount of foamed compound used to coat a textile can vary widely, from 0.053 kg / m2 to 0.84 kg / m2 of dry weight, depending on the characteristics of the textile, the weight of the desired coating and its thickness. For example, with foams having a thickness of 3 to 6 mm, the preferred weight of the coating is 0.067 kg / m2 to 0.4 kg / m2 dry weight. For foams having a thickness of approximately 12 mm, the preferred coating weight is from 0.335 kg / m2 to 0.85 kg / m2 dry weight. In preparing the substrates with polyurethane foam backing of the present invention, in general, and textiles with backing in particular, it is advantageous to dry the foamed polyurethane Compound as quickly as possible after applying it to the substrate. It is particularly advantageous to carry out at least one initial drying of a foamed polyurethane Compound of the present invention, using an infrared heater, since this practice can promote the formation of a uniform skin on the surface of the foam facing the heater, which at the same time is aesthetically convenient and can be enhanced or subjected to some other form of marking process. To assist in placing the foamed composite composition on another material, it is advantageous to incorporate a "skid" auxiliary into the foam formulation, or to add an additional skimmer layer, before completing the curing of the polyurethane foam, or thereafter. Said auxiliaries modify the coefficient of friction properties of the foam surface and allow the mixed composition to slide into place for easier handling. Said sliding aids include laminated polyolefin films, sprayed on Teflon coatings, silicones, etc. Components that can be incorporated in the foam include waxes, particularly wax emulsions that are compatible with the various components of the Compound. One property of the polyurethane foams of the present invention is that they are more resistant to yellowing. Conventional polyurethane foams, particularly those prepared with aromatic starting materials, such as MDI or TDI, may yellow when exposed to air and ultraviolet light. The foams of the present invention have a surprising ability to resist yellowing under conditions that would cause rapid yellowing in a conventional polyurethane foam. In producing the compound, surfactants are generally added to the polyurethane dispersion, together with antioxidants, bactericides, etc., since the viscosity is low and good mixing is obtained. Then the dispersion aid must be added, followed by the inorganic charge, slow enough to ensure good dispersion and avoid the lumping / lumping of the load. Finally the thickener is added to obtain the required viscosity of the compound. In the present application it is believed that the addition of ammonium stearate after the addition of the filler and the thickener, avoids the "lynching of the polyurethane dispersion particle, which results in lower viscosity of the Compound during mixing.The following examples are given to illustrate the present invention.The examples are not intended to limit the scope of the present invention. invention and should not be interpreted in that way, all percentages are by weight, unless otherwise noted.

EXAMPLES Materials used in the examples PREPARATION OF A PRE-POLYMER A prepolymer is prepared by adding 504 g of VORANOL 4701, 14 g of MPEG 950, 9.19 g of diethylene glycol, 86.45 g of ISONATE 125M and 86.45 g of ISONATE 50 OP, in a glass bottle , where the threads of the glass bottle are wrapped with TEFLON * tape to prevent the lid from adhering to the bottle (* A DUPONT brand designation). The bottle is sealed, shaken vigorously until the components are homogeneous, and then rolled in a bottle spinner for approximately 10 minutes. The bottle is then placed in an oven maintained at 70 ° C for 15 hours; after which it was removed and allowed to cool to room temperature before use.

PREPARATION OF AN AQUEOUS POLYURETHANE DISPERSION A polyurethane dispersion is prepared by extending the prepolymer chain in water with piperazine, at a stoichiometry of 0.7, at a solids content of 52.7 percent. The dispersion is prepared with 3 percent of the surfactant BIO-TERG AS-40, based on the solids of the prepolymer. The polyurethane dispersion has an average particle size by volume of 0.229 microns.

EXAMPLE 1 PREPARATION OF A FOAMED POLYURETHANE FOAM ELASTIC. LOW DENSITY The following compound, shown in Table 1, is prepared at room temperature, and allowed to stand for about one hour, to allow the viscosity to accumulate.

TABLE 1 foam the composite using an Oakes laboratory mixer (E. T. Oakes Corporation, Hauppauge, New York), at a density of approximately 110 grams per liter, and empty onto a non-woven, non-coated polyester fabric, at a thickness of 3.6 millimeters. The foam is dried for 10 seconds under infrared heating, followed by 20 minutes in an oven at 143 ° C. The results of the foam test are shown later in Table III.

EXAMPLE 2 PREPARATION OF FOAMED POLYURETHANE FOAM. ELASTIC. LOW DENSITY. FOR APPLICATIONS RESISTANT TO FLAMES The following compound, shown in Table 11, is prepared at room temperature, and allowed to stand for approximately one hour, to allow the viscosity to build up.

TABLE II The compound of Table II is foamed using an Oakes Laboratory mixer (E. T. Oakes Corporation, Hauppauge, New York), at a density of approximately 110 grams per liter. The foam is then emptied to a thickness of approximately 3.5 millimeters, on a non-woven, non-coated polyester fabric. The fabric should be heated to 25-50 ° C during the emptying process. The foam is then dried for 5 to 10 seconds, under infrared heat, and then for 20 minutes in a convention oven, at 143 ° C. The results of the foam test are given below in Table III.

TABLE III EXAMPLE 3 PREPARATION OF A FOAMED FOAM OF ELASTIC POLYURETHANE. OF LOW DENSITY, FOR APPLICATIONS OF RESISTANCE TO FLAMES The following compound, shown in Table IV, is prepared at room temperature, and allowed to stand for about one hour to allow the viscosity to build up.

TABLE IV The compound described in Table IV was molded on a commercial grade polyester fabric. Samples of the fabric were tested for flammability resistance, according to FMVSS 302, before applying the coating. Mixed foam / cloth structures were also tested for their resistance to flammability, after drying. The results of the test are given in table V.

TABLE V Although the invention has been described in detail in the foregoing, for purposes of illustration, it should be understood that those details are only for that purpose, and that those skilled in the art can make variations without departing from the spirit and scope of the invention.

Claims

1. - A process to form a mixed foam structure of two or more components, obtained by adhesion of a polyurethane foam on a substrate; characterized in that it comprises the steps of: foaming an aqueous polyurethane formulation, applying the foam to a substrate, and drying the foam to a dry foam, where the dry foam has a dry density of 35 kg / m3 to 160 kg / m3; where the polyurethane formulation is prepared from a polyurethane dispersion, a foaming surfactant and a stabilizing surfactant. 2 - The process according to claim 1, further characterized in that the polyurethane dispersion is prepared by mixing water, a chain extender, a surfactant, a urethane prepolymer, under sufficient mixing conditions to prepare a stable dispersion. 3. The process according to claim 2, further characterized in that the surfactant is an anionic surfactant. 4. The process according to claim 1, further characterized in that the foaming surfactant is a carboxylic acid salt. 5. The process according to claim 4, further characterized in that the foaming surfactant is one or more surfactants of the formula: RC02"X + (Formula I), wherein R represents a linear or branched alkyl of 8 to 20 carbon atoms, which may contain an aromatic, a cycloaliphatic or a heterocycle, and X is an opposite ion. according to claim 5, further characterized in that X + is Na, K or an amine 7. - The process according to claim 6, further characterized in that X + is NH4 + 8. - The process according to claim 4, further characterized in that the surfactant is present in an amount of 1 to 15 parts of surfactant by dry weight, per 100 parts of solids of the polyurethane dispersion 9. The process according to claim 7, further characterized in that surfactant agent is ammonium stearate 10. The process according to claim 1, further characterized in that the stabilizing surfactant is an anionic surfactant, based on at least one salt Sulfonic acid 11. The process according to claim 10, further characterized in that the stabilizing surfactant is one or more surfactants of the formula: R2OOCCH2CH (S03"M +) COOR2 (formula 2) wherein R2 in each occurrence is independently a linear or branched alkyl of 6 to 20 carbon atoms, which may contain an aromatic or a cycloaliphatic; and M is an opposite ion. 1

2. The process according to claim 11, further characterized in that it is ammonia or a member of group 1A of the Periodic Table. 1

3. The process according to claim 12, further characterized in that the surfactant is an octadecyl sulfosuccinate salt. 1

4. - The process according to claim 11, further characterized in that the stabilizing surfactant is present in an amount of 0.01 to 10 parts of dry surfactant per 100 parts of solids of the polyurethane dispersion. 1

5. - The process according to claim 1, further characterized in that the formulation contains a flame retardant, so that the mixed foam composition passes the combustion modification test FMVSS 302. 1

6. - The process of compliance with claim 15, further characterized in that the flame retardant is a phosphonate ester, a phosphate ester, a halogenated phosphate ester, a dehydratable flame retardant, or a mixture thereof. 1

7. - The compliance process, with claim 16, further characterized in that the flame retardant is a dehydratable flame retardant, selected from alkali silicates, zeolites or other hydrated phosphates; borosilicates or borates, aluminum hydroxides, cyanuric acid derivatives, phenol, melamine or urea-formaldehyde resins, graphites and mica which are capable of swelling; vermiculites and pearls. 1

8. - The process according to claim 17, further characterized in that the flame retardant is an aluminum hydroxide, hydrated aluminum oxides, hydrated alumina or a mixture thereof. 1

9. - The process according to claim 17, further characterized in that the flame retardant is present in an amount of 5 to 120 parts per 100 parts of dispersion solids. 20. - The process according to claim 1, further characterized in that the substrate of a textile, a plastic film, a synthetic sheet or paper is selected. 21. - The process according to claim 20, further characterized in that the substrate is a polyvinyl sheet. 22. - The process according to claim 20, further characterized in that the substrate is a textile. 23. - A mixed structure of flexible textile-polyurethane fabric, characterized in that it consists of a woven fabric; the fabric having been coated, on at least one of its sides, with a flexible foam having a dry density of 35 kg / m3 to 160 kg / m3; wherein the foam is derived from a foamed polyurethane composition comprising a dispersion of polyurethane, surfactants and other additives known per se to produce said flexible polyurethane foams. 24. - The mixed structure according to claim 23, further characterized in that the surface properties of the foam are modified by inclusion of a wax in the polyurethane foamed composition, at a preferred level of 1.0 to 10.0 parts per 100 parts of solids of the dispersion. 25. - The mixed structure according to claim 23, further characterized in that the properties of the surface of the foam, opposite the surface fixed to the fabric, are modified by application of a silicone polymer, preferably as an emulsion or water-based dispersion, by means of a sprinkling process or a roller coating process. 26. - The mixed structure according to claim 23, further characterized in that a non-woven polyethylene, of light weight, is applied to the flexible foam, by a hot rolling process, at pressures and temperatures that do not adversely affect the textile nor foam, by producing the mixed structure of three components.